refactor: use resourceForReadableStream for fetch (#20217)

Switch `ext/fetch` over to `resourceForReadableStream` to simplify and
unify implementation with `ext/serve`. This allows us to work in Rust
with resources only.

Two additional changes made to `resourceForReadableStream` were
required:

- Add an optional length to `resourceForReadableStream` which translates
to `size_hint`
 - Fix a bug where writing to a closed stream that was full would panic

1 files changed, 6 insertions, 2 deletions

diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
index 4f472984d..9fc15d1ad 100644
--- a/ext/web/06_streams.js
+++ b/ext/web/06_streams.js
@@ -12,6 +12,7 @@ const {
   op_arraybuffer_was_detached,
   op_transfer_arraybuffer,
   op_readable_stream_resource_allocate,
+  op_readable_stream_resource_allocate_sized,
   op_readable_stream_resource_get_sink,
   op_readable_stream_resource_write_error,
   op_readable_stream_resource_write_buf,
@@ -863,13 +864,16 @@ function readableStreamReadFn(reader, sink) {
  * read operations, and those read operations will be fed by the output of the
  * ReadableStream source.
  * @param {ReadableStream<Uint8Array>} stream
+ * @param {number | undefined} length
  * @returns {number}
  */
-function resourceForReadableStream(stream) {
+function resourceForReadableStream(stream, length) {
   const reader = acquireReadableStreamDefaultReader(stream);
 
   // Allocate the resource
-  const rid = op_readable_stream_resource_allocate();
+  const rid = typeof length == "number"
+    ? op_readable_stream_resource_allocate_sized(length)
+    : op_readable_stream_resource_allocate();
 
   // Close the Reader we get from the ReadableStream when the resource is closed, ignoring any errors
   PromisePrototypeCatch(